1. Field of the Invention
The present invention relates to a thermal transfer printer, and particularly to a thermal transfer printer which obtains a high-quality printed image that is not dull, by means of smoothing the surface of the image following printing.
2. Description of the Prior Art
Thermal transfer printers which are a type of recording apparatus are generally and widely used a output devices for computers, word processors, and the like, due to characteristics thereof such as high recording quality, low noise, low cost, and ease of maintenance.
Such known thermal transfer printers are constructed such that a carriage is enabled to reciprocally move along a platen, a thermal head formed of an array of a plurality of heat-emitting devices is provided to this carriage, and a ribbon cassette storing an ink ribbon of a desired color is detachably mounted thereto.
The ink ribbon fed from the aforementioned ribbon cassette and the printing paper are held between the aforementioned platen and thermal head, the thermal head is caused to move reciprocally with the carriage along the platen, and by means of selectively causing electroconducting of the heat-emitting devices of the aforementioned thermal head based on recording information while spooling the aforementioned ink ribbon, the ink of the ink ribbon is partially transferred into the paper, thereby recording the desired characters or images thereon.
Also, in the case of performing full-color printing on the paper, three ribbon cassettes storing ink ribbons formed of ink of at least the three colors of yellow, magenta, and cyan, are provided. Each of the ribbon cassettes are automatically exchanged between the carriage for recording.
Regarding such known thermal transfer printers, a widely known method is to record on recording paper using an ink ribbon comprised of a resin film of a material such as PET (polyethylene-terepthalate) coated with heat-melt ink, but in recent years, a method has come to be known in which an ink ribbon coated with heat-sublimation ink is used for recording on paper.
Of these, in the event that the method of recording on paper using the ink ribbon comprising heat-melt ink is employed, the user can record of a wide variety of mediums, such as plain paper, cardboard, postcards, etc. In this way, this method exhibits excellent useability.
On the other hand, in the event that the ink ribbon comprising heat-sublimation ink is used, or in more specific terms, in the event that recording on paper is performed using an ink ribbon formed by coating a base of material formed from a resin film such as PET or the like with heat-sublimation ink, the amount of sublimation of the heat-sublimation ink can be adjusted by means of controlling the energy applied to the thermal head, thus allowing adjustment of the concentration of the image recorded on the paper. Hence, a full-color image rivaling the image quality of silver-salt photography can be obtained by using a special paper of which surface has been treated. Thus, thermal transfer printers using ink ribbons comprised of heat-sublimation ink have come to be widely used as high-quality video printers.
However, regarding thermal transfer printers which use ink ribbons comprised of the aforementioned heat-melt ink, and particularly regarding thermal transfer printers which use ink ribbons comprised of heat-melt ink wherein resin has been used as a coloring agent and also a binder, the surface of the ink transferred onto the paper may be uneven due to peeling of the ink ribbon at the time of transferring/recording, the edge portion of the transferred dots may be peeled back, and further in the event that recording of full-color images using ink of the three colors, yellow, magenta, and cyan is performed, a great deal of unevenness has been generated on the surface of the image recorded on the paper, owing to up to three ink colors being overlaid.
Accordingly, unevenness on the surface of the image causes irregular reflection of white light at this portion, deterioration of saturation creates the problem of dullness, and this has been an obstruction in obtaining a recorded image of higher quality.
Also, regarding thermal transfer printers which use ink ribbons comprised of the aforementioned heat-sublimation ink, in the event that heat-sublimation ink is transferred onto the paper to record the desired image on the paper, the amount of energy supplied to the thermal head for heat-sublimation of the heat-sublimation ink on the ink ribbon is small at portions where the color of the recorded image is light and the concentration is low, and as a result, the heat-sublimation ink transferred onto the paper is smooth and the obtained image is glossy and vivid. On the other hand, the amount of energy supplied to the thermal head for heat-sublimation of the heat-sublimation ink on the ink ribbon is great at portions where the recorded image is black and the concentration is high, and as a result, so-called matting wherein the image transferred to the paper becomes dull due to thermal warping of the surface of the paper, and consequently, glossy portions and dull portions exist in the recorded image in a mixed manner, and this has been an obstruction in obtaining a recorded image of higher quality.
Also, there has been the problem that this matting is exhibited even more markedly in the event that recording of full-color images using heat-sublimation ink of the three colors, yellow, magenta, and cyan is performed.